Photoelectric probes for determining the density of body tissue for x-ray purposes

ABSTRACT

An internal probe to be inserted in the mouth and an external probe to be positioned externally of the mouth in alignment with the internal probe, said probes projecting in substantially parallel relation from a handle member, the internal probe terminating in a photoelectric cell and the external probe terminating in a light source optically aligned with said photocell so as to project light through the mouth tissue to said photocell to activate a meter, the reading of which is proportionate to the opaqueness or density of the intervening tissue so as to provide means for determining in advance the apparatus exposure time necessary to obtain an acceptable X-ray picture of the intervening tissue.

United States Patent Hepp et al.

[ air, 14, 11972 Colo. 80516; Gary E. Roberts, 101 West 1st St.,Loveland, Colo. 80206 {22] Filed: June 25,1969

[21] Appl.No.: 836,315

Kompelien ..128/2.05

Primary Examiner-Richard A. Gaudet Assistant Examiner-Kyle L. HowellAttorney-R. H. Galbreath [5 7] ABSTRACT An internal probe to be insertedin the mouth and an external probe to be positioned externally of themouth in alignment with the internal probe, said probes projecting insubstantially parallel relation from a handle member, the internal probeterminating in a photoelectric cell and the external probe terminatingin a light source optically aligned with said photocell so as to projectlight through the mouth tissue to said photocell to activate a meter,the reading of which is proportionate to the opaqueness or density ofthe intervening tissue so as to provide means for determining in advancethe apparatus exposure time necessary to obtain an acceptable X- raypicture of the intervening tissue.

6 Claims, 6 Drawing Figures PIIOTOEILECTRIC PROBES FOR DETERMINING THEDENSITY OF BODY TISSUE FOR X-RAY PURPOSES This invention relates tomeans for determining in advance the proper X-ray camera exposures to beused to produce the most effective photographic results in a givensituation. Since X-ray films are produced by the passage of rays throughintervening tissue and since the density of the tissue of course affectsthe passage of the rays it is difficult to assume in advance the correctexposure that will be required in the many different situationsencountered in actual practice. It is usually a case of trial anderror." This often requires additional time and film to correct theoverexposed and underexposed trials.

The principal object of this invention is to produce a relativelysimple, easily used exposure meter for X-ray photographs which willenable the user to readily and accurately determine in advance theexposure time that will be required to obtain the best result in eachspecific case so as to avoid the loss of time and materials occasionedby the present trial and error methods.

While the invention is similarly useful in many X-ray problems it isparticularly adaptable, but not limited, to use by the dental professionwhere rapid X-rays are required to further the work being performedwhile the patient remains in place in the dental chair.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efficiency.These will become more apparent from the following description.

In the following detailed description of the invention, reference ismade to the accompanying drawing which forms a part hereof. Likenumerals refer to like parts in all views of the drawing and throughoutthe description.

In the drawing:

FIG. 1 is a side view of the probe of this invention illustrating inbroken line the relative position of a patient upon which the probe isbeing used;

FIG. 2 is a front view of the probe;

FIG. 3 is a cross'sectional view looking downwardly on the line 3-3,FIG. 1;

FIG. 4 is a fragmentary longitudinal section taken on the line 44, FIG.2;

FIG. 5 is a top view of the probe; and

FIG. 6 is a circuit diagram suggesting how the probe may be combinedwith amplifying and metering circuits.

Briefly, the probe comprises a handle block 10, preferably formed ofmolded plastic, from the upper extremity of which a light stem 11 and atubular metallic photoelectric cell stem 12 project in substantiallyparallel relation. The light stem 11 terminates in a relatively widehollow lamp head 13 having a removable lens bezel 14 which supports anelongated projection lens I5 thereon, The photocell stem 12 terminatesin a substantially cylindrical cup-shaped cell head 16 having aremovable lens bezel 17 which supports an elongated light receiving lens18 thereon. The stems 11 and 12 are so contoured that the lenses and 18face each other in axial alignment.

A suitable, conventional photoelectric type incandescent lamp I9 ismounted in the lamp head 13 so as to project a light beam A" through thelenses l5 and 18 into a herrnatically sealed photocell 20, of thelight-controlled variable resistor type, which is mounted in the cellhead 16.

The lower extremity of the tubular photocell stem 12 is fixedly mountedin a suitable receiving socket 21 in the top of the handle block 10. Thelower extremity of the tubular light stem 11 is fixedly mounted in asocket 22 in the top of a vertically elongated shiftable socket element23 positioned in a vertical cavity 21 in the handle block. The shiftablesocket element 23 is preferably substantially square in cross sectionand is positioned between the side walls of the cavity 23 which istransversely widened to allow the lateral shifting of the socket elementin the handle block for varying the distance between the lamp head 13and the cell head 16. The socket element 23 is slidably mounted on, andmaintained vertical in the cavity 24 by, two horizontal, verticallyspaced guide rods 25 which pass through the handle block and are rigidlymounted therein by means of terminal clamp screws 26.

The socket element 23 can be shifted along the guide rods 25 in anydesired manner. As illustrated, the shifting is accomplished by fixedlymounting a rotary type potentiometer 27, having a threaded shaft 28, inone side of handle block between the guide rods 25 and extending itsshaft 28 across the cavity 24 and through a threaded hole in the socketelement so as to terminate in a knurled adjusting knob 29 at the otherside of the handle block. It can be seen that reciprocal rotation of theknob 29 will cause the socket element to reciprocally travel along theguide rods.

For the purpose of clarity the conventional wiring and connections havebeen omitted from the sectional views of the drawing and are showndiagrammatically in FIG. 6 of the drawing in which a conventionalphotoelectric power supply is indicated at 30 fed from the I 10 v. housecircuit as indicated at 31. The power supply furnishes the correctvoltage through lamp leads 32 to properly illuminate the lamp 1), andalso receives the output of the photocell 20 through photocell leads 33and amplifies the same to actuate a suitable milliammeter 34. The lampleads 32 and the photocell leads 33 are inclosed in a suitable flexiblemultiple cord 35 leading from the handle block to the power supply 30.

It will be noted that the potentiometer 27 is connected in se' ries withthe lamp leads 32 so that the rotation of the potentiometer shaft 28serves a double purpose. It provides means for clamping the lenses l5and 18 snugly against the opposite sides of the intervening tissue andit provides means for automatically and proportionately varying the lampintensity in correspondence with the varying separations between thelight source and the photocell. The potentiometer 27 and the threads onits shaft 28 are accurately pre-positioned so as to maintain theintensity of the light impinging upon the photocell uniform at allpossible separations between the lamp and the cell so that the variationof the readings of the meter 34 will be unaffected by the separations,so as to be an index of tissue density only.

For dental use, the stems I1 and 12 are separated and the cell head 16is positioned within the mouth at the point of operation and the lamphead 13 is positioned against the face above the lip, as shown inFIG. 1. The knob 29 is then rotated to bring the lenses 15 and 18 andtheir bezels I4 and 17 against the tissue so as to shield againstexternal light. The meter 34 is then read to obtain the desired indexfor proper X- ray exposure.

While a specific form of the invention has been described andillustrated herein, it is to be understood that the same may be variedwithin the scope of the appended claims, without departing from thespirit of the invention.

Having thus described the invention what is claimed and desired to besecured by Letters Patent is:

1. A photoelectric probe for determining the density of body tissue forX-ray purposes comprising:

a. a handle element;

b. a first stem mounted in and projecting from said handle element;

c. a second stem mounted in and projecting from said handle elementadjacent to said first stem;

d. a photoelectric cell supported by said second stern;

e. a light source supported by said first stem so as to project a beamof light against said photoelectric cell;

f. means for supplying electrical power to said light source;

g. meter means connected with said photoelectric cell and acting toindicate the electric alterations caused by the incidence of said beamupon said cell;

h. means in said handle element for adjustably varying the distancebetween said light source: and said photoelectric cell;

i. means in said handle element for varying the intensity of said beam;

j. the means for varying the intensity of said beam is connected to andactuated by the means for varying the distance between said light sourceand said photoelectric cell whereby the intensity of said light sourcedecreases as the distance between said light source and said celldecreases; and

k. a socket element shiftably mounted in said handle element, said firststem being mounted on said socket element for movement therewith.

2. A photoelectric probe as described in claim 11 having:

a. a cavity formed in said handle member;

b. said socket element positioned in, and shiftable from side to side ofsaid cavity,

c. means for shifting said socket member from side to side of saidcavity; and

d. means for maintaining said socket member aligned in said cavity atall shiftably-attained positions.

3. A photoelectric probe as described in claim 2 in which the means formaintaining said socket member aligned comprises;

a. a pair of parallel guide rods extending across said cavity throughsaid socket member in the plane of said stems, said socket member beingslidably fitted on said rods so as to be maintained vertical thereby.

4. A photoelectric probe as described in claim 3 in which the means forshifting said socket member comprises:

a. shaft-supporting means fixedly mounted in said handle element at oneside of said cavity between said guide rods;

b. a rotatable threaded shaft extending from said shaft-supporting meansacross said cavity parallel to said rods, said socket member beingthreaded upon said shaft so that reciprocal rotation of the latter willimpart reciprocal movement of said socket member along said rods.

5. A photoelectric probe as described in claim 3 in which the means forshifting said socket member comprises:

a. a rotary-type potentiometer fixedly mounted in said handle element atone side of said cavity between said guide rods;

b. a threaded potentiometer-actuating shaft extending from saidpotentiometer across said cavity parallel to said rods, said socketmember being threaded upon said shaft so that reciprocal rotationthereof of the latter will impart movement of said socket member alongsaid rods.

6. A photoelectric probe as described in claim 5 in which:

a. the potentiometer is connected in series with the power supply to thelight source so that rotation of said shaft simultaneously shifts thesocket element and varies the intensity of the light source.

1. A photoelectric probe for determining the density of body tissue forX-ray purposes comprising: a. a handle element; b. a first stem mountedin and projecting from said handle element; c. a second stem mounted inand projecting from said handle element adjacent to said first stem; d.a photoelectric cell supported by said second stem; e. a light sourcesupported by said first stem so as to project a beam of light againstsaid photoelectric cell; f. means for supplying electrical power to saidlight source; g. meter means connected with said photoelectric cell andacting to indicate the electric alterations caused by the incidence ofsaid beam upon said cell; h. means in said handle element for adjustablyvarying the distance between said light source and said photoelectriccell; i. means in said handle element for varying the intensity of saidbeam; j. the means for varying the intensity of said beam is connectedto and actuated by the means for varying the distance between said lightsource and said photoelectric cell whereby the intensity of said lightsource decreases as the distance between said light source and said celldecreases; and k. a socket element shiftably mounted in said handleelement, said first stem being mounted on said socket element formovement therewith.
 2. A photoelectric probe as described in claim 11having: a. a cavity formed in said handle member; b. said socket elementpositioned in, and shiftable from side to side of said cavity, c. meansfor shifting said socket member from side to side of said cavity; and d.means for maintaining said socket member aligned in said cavity at allshiftably-attained positions.
 3. A photoelectric probe as described inclaim 2 in which the means for maintaining said socket member alignedcomprises; a. a pair of parallel guide rods extending across said cavitythrough said socket member in the plane of said stems, said socketmember being slidably fitted on said rods so as to be maintainedvertical thereby.
 4. A photoelectric probe as described in claim 3 inwhich the means for shifting said socket member comprises: a.shaft-supporting means fixedly mounted in said handle element at oneside of said cavity between said guide rods; b. a rotatable threadedshaft extending from said shaft-supporting means across said cavityparallel to said rods, said socket member being threaded upon said shaftso that reciprocal rotation of the latter will impart reciprocalmovement of said socket member along said rods.
 5. A photoelectric probeas described in claim 3 in which the means for shifting said socketmember comprises: a. a rotary-type potentiometer fixedly mounted in saidhandle element at one side of said cavity between said guide rods; b. athreaded potentiometer-actuating shaft extending from said potentiometeracross said cavity parallel to said rods, said socket member beingthreaded upon said shaft so that reciprocal rotation thereof of thelatter will impart movement of said socket member along said rods.
 6. Aphotoelectric probe as described in claim 5 in which: a. thepotentiometer is connected in series with the power supply to the lightsource so that rotation of said shaft simultaneously shifts the socketelement and varies the intensity of the light source.